The present invention relates to electric coils used in motor vehicle sensors and actuators.
Most motor vehicles include a plethora of sensors and actuators incorporated into the vehicle control systems, such as the anti-lock braking system (A.B.S.), the traction control system (T.C.S.), and the vehicle stability enhancement control system (V.S.E.). Many of-the sensors and actuators used in these controls systems include an electric coil that is used to move a plunger when energized or to provide a signal in response to a change in magnetic flux around the coil.
In general, these coils include a spool with wire wound around it numerous times. The ends of the wire are connected to terminals that, in turn, can be electrically connected to a control system to allow the coil to be energized or to send a signal to the control system.
It happens that termination point electrical isolation requirements must be met in order for the coil to function properly. Traditional methods of isolation include placing a plastic sleeve or clip over the wire and terminal connection point and then shrink wrapping the entire coil assembly. This method includes several added process steps which consume time and increase manufacturing costs.
Accordingly, the present invention recognizes the need for a coil in which the coil wire is connected to the terminals and then isolated in a manner that minimizes manufacturing time and costs.
A coil assembly includes a spool that has a top and a bottom. The spool forms a groove near the top and a winding bay between the groove and the bottom of the spool. At least one ramp is formed in the groove. Moreover, the coil assembly includes at least two terminal posts and each terminal post has a foot that is disposed within the groove.
As described in detail below, each terminal post is movable between a winding position, wherein the respective foot protrudes outwardly from the spool, and a retracted position wherein the foot is disposed behind a ramp. Furthermore, at least one wire is included and each wire has at least two ends. The wire is wrapped around the winding bay to form a coil and the ends of the wire are connected to respective terminal posts.
As envisioned in a preferred embodiment and described in detail below, the spool has an upper flange and a medial flange, between which the groove is established. Moreover, the spool includes a lower flange. A winding bay is established between the lower flange and the medial flange. Preferably, the upper flange forms at least two holes that are sized to receive the terminals.
In a preferred embodiment, the spool has at least two terminal support collars that extend from the upper flange. Each support collar forms a hole that is sized to receive a terminal. Furthermore, the coil assembly includes a protective shroud that is disposed around the coil. Also in a preferred embodiment, each terminal foot includes a heel and a toe and the ramps are configured in such a manner that the lower portion of each ramp is closest to the heel of the terminal foot. As the terminal is rotated, the toe of the terminal foot rides up the ramp until the terminal foot snaps behind the ramp into the retracted position.
In another aspect of the present invention, a coil assembly includes a spool that defines a groove. A coil of wire is wound on the spool and the coil defines two ends. Moreover, the coil assembly includes at least two terminal posts that are movable on the spool between a winding position, wherein a respective end can be engaged with the post, and a retracted position, wherein the respective end is disposed in the groove.
In yet another aspect of the present invention, a coil assembly is manufactured by providing a spool that has a center, a top, a bottom, a winding bay between the top and bottom, and a groove between the top and the winding bay. Also, at least one ramp is formed in the groove and at least two metal terminal posts, each terminal post having a foot, is inserted through the spool such that the foot is within the groove. Moreover, at least one wire having at least two ends is provided and wrapped around the winding bay to form a coil.
In this aspect of the present invention each end of the wire is wrapped around a respective terminal foot and then each end of the wire is soldered in place. Once the ends of the wire are attached to the terminal feet, each terminal post is rotated so that the respective terminal foot rotates toward the center of the spool until each terminal foot is retracted within the groove.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: